<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>v-bind</title>
    <style>
        .selector{
           width: 100px;
            height: 100px;
        }
    </style>
</head>
<body>
<div id="app">
    <div @mouseenter="info=1" v-bind:class="{selector:info===1}" style="border: 1px red solid">1</div>
    <div @mouseenter="info=2" v-bind:class="{selector:info===2}" style="border: 1px blue solid">2</div>
    <div @mouseenter="info=3" v-bind:class="{selector:info===3}" style="border: 1px pink solid">3</div>

</div>

<script src="../node_modules/vue/dist/vue.js"></script>
<script>
    let app = new Vue({
        el: "#app",
        data: {
            info:1
        }

    });
</script>

</body>
</html>